What did he say? Did he invite a response or just try to shove something at you? Is he still practicing? If he is, or perhaps even if he isn't, I think if it were me I would send one. They may not be able to hear but that's not our responsibility. They need to start taking into account and dealing with the damage they do and all we can do is to try to get our message out there. (Oops, no pun intended.)